1. Technical Field
The present invention relates to devices for cooling substances such as, for example, integrated circuit chips, and more particularly, the present invention relates to thermoelectric coolers.
2. Description of Related Art
As the speed of computers continues to increase, the amount of heat generated by the circuits within the computers continues to increase. For many circuits and applications, increased heat degrades the performance of the computer. These circuits need to be cooled in order to perform most efficiently. In many low end computers, such as personal computers, the computer may be cooled merely by using a fan and fins for convective cooling. However, for larger computers, such as main frames, that perform at faster speeds and generate much more heat, these solutions are not viable.
Currently, many main-frames utilize vapor compression coolers to cool the computer. These vapor compression coolers perform essentially the same as the central air conditioning units used in many homes. However, vapor compression coolers are quite mechanically complicated requiring insulation and hoses that must run to various parts of the main frame in order to cool the particular areas that are most susceptible to decreased performance due to overheating.
A much simpler and cheaper type of cooler are thermoelectric coolers. Thermoelectric coolers utilize a physical principle known as the Peltier Effect, by which DC current from a power source is applied across two dissimilar materials causing heat to be absorbed at the junction of the two dissimilar materials. Thus, the heat is removed from a hot substance and may be transported to a heat sink to be dissipated, thereby cooling the hot substance. Thermoelectric coolers may be fabricated within an integrated circuit chip and may cool specific hot spots directly without the need for complicated mechanical systems as is required by vapor compression coolers.
Many types of thermoelectric coolers are not as efficient as vapor compression coolers requiring more power to be expended to achieve the same amount of cooling. However, a recent improvement in thermoelectric coolers using quantum cold point coolers as described in U.S. patent application Ser. No. 10/015,237 filed Dec. 13, 2001 and incorporated herein by reference, improves the performance of thermoelectric coolers significantly demonstrating thermodynamic cooling efficiencies comparable to the mechanical vapor compression refrigerators. The construction of these quantum cold point coolers consists in the assembly of two partsxe2x80x94a substrate with sharp cold points overcoated with thermoelectric materials and a substrate with planar thermoelectric films. The assembly is difficult and the bonding is usually performed using passive adhesives or films of low thermal conductivity. However, it would be desirable to have a better and more robust method for assembling the two sub-components of the quantum cold point cooler to form a complete thermoelectric cooler.
The present invention provides a thermoelectric cooler and a system and method for fabricating the thermoelectric cooler. In one embodiment, the thermoelectric cooler includes a first magnetic element, a second magnetic element composed of magnetic or magnetically susceptible material, a first thermoelectric sub-component, and a second thermoelectric sub-component. The first thermoelectric sub-component and the second thermoelectric sub-component are situated between the first and second magnetic elements. The first and second magnetic elements are selected such that a compressive force is exerted on the first and second thermoelectric elements. The magnetic elements are selected and adjusted in magnetic attraction such that the force exerted on the first and second thermoelectric elements establishes and maintains a contact of selected pressure between the first and second thermoelectric sub-components. Preferably, one of the magnetic elements is an electromagnet and the other magnetic element is a ferrous magnetically susceptible material or a permanent magnet. The current through the electromagnet is chosen such that the force, whether attractive or repulsive, increases or decreases the pressure as appropriate to produce a compressive force of specified pressure which is desired for optimal or near optimal operation of the thermoelectric cooler.